One of the most serious limiting factors to cowpea (Vigna unguiculata L.) production in arid and semi-arid areas is drought stress. This paper has examined the elastic co-action of nano-ascorbic acid (nano-AsA) and green-synthesized iron nanoparticles (FeNPs) applied as a folaric acid on cowpea growth, physiology, and yield during varying irrigation regimes. The experiment was a field experiment that was performed during summer in the year 2024 in Najaf, Iraq and was split-plot in nature with three replications. Irrigation treatments included 50% (I₁), 60% (I₂), and 70% (I₃) depletion of available soil water, while foliar treatments consisted of distilled water (T₀), nano-AsA (50 mg L⁻¹; T₁), green-synthesized FeNPs (50 mg L⁻¹; T₂), and their combination (T₃). The FeNPs were synthesized through the green synthesis, which is environmentally friendly using the Moringa oleifera leaf extract, whereas the nano-AsA was synthesized by the ultrasonication. Findings revealed that the drought stress seriously diminished the height of plants, leaf area, number of pods and seeds per plant, dry biomass, and grain yield and increased proline content and activity of peroxidase. Application of nano-AsA and FeNPs (particularly their combination) alleviated the negative impact of drought through the promotion of antioxidant defenses, vegetative growth, and reproduction. Combined treatment (T 3) was always better than the individual application which led to delayed flowering, high biomass, and yield stability at stress levels. The results of the study indicate the possibility of combining nano-AsA and green-synthesized FeNPs as a new and greener approach to enhancing drought resistance and sustainable cowpea growth.